It has been shown that cerebral oxygenation measured by near infrared spectroscopy is reduced by intravenous application of norepinephrine. Otherwise, intravenous nitroglycerine increases cerebral oxygenation during cardiopulmonary bypass. Hence, cafedrine/theodrenalin and urapidil may also have an effect on cerebral perfusion. In this prospective randomized study the effect of cafedrine/theodrenalin and urapidil on cerebral oxygenation measured by near infrared spectroscopy is investigated.